CDP1871AC PDF File ( Datasheet )

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ CMOS Peripherals CDP1871A,CDP1871AC ~VDD , " t SliiFT J 38 1 CONTROL 4 37t--- ALPHA 3'5f-- DEBOUNCE 06-- 6 " 33 ............. DA f--32f-- BUS 7 31 BUS (; 3O~BUS" 29>-- BUS 4 2Bf-- BlJS 3 ::3::'-"'E"" 26 - BBUUSS2! ~~; 0 19 22 C52 20 21 e5i TOP VIEW TERMINAL ASSIGNMENT CMOS Keyboard Encoder Features: Directly interfaces with COP1BOO-series microprocessors Low power dissipation 3-state outputs Scans and generates code for 53 key ASCII keybo

CDP1871A, CDP1871AC REFERENCE APP NOTE 7374 August 1996 CMOS Keyboard Encoder Description The CDP1871A is a keyboard encoder designed to directly interface between a CDP1800-series microprocessor and a mechanical keyboard array, providing up to 53 ASCII coded keys and 32 HEX coded keys, as shown in the system diagram (Figure 1). The keyboard may consist of simple single-pole single-throw (SPST) mechanical switches. Inputs are provided for alpha-lock, control, and shift functions, allowing 160 u